System for providing assist torque based on a vehicle state

Abstract

A control system for providing an assist torque is provided. The control system includes a control algorithm module and a comfort limit module. The control algorithm module calculates a corrective steering torque based on a target vehicle state and an estimated vehicle state. The comfort limit module receives a handwheel torque. The comfort limit module calculates a limited corrective steering torque based on the corrective steering torque and the handwheel torque. The limited steering torque represents an allowable amount of the assist torque provided by the control system.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a system for providing an assist torque and in particular to a system for providing the assist torque that is based on a target vehicle state and an estimated vehicle state.BACKGROUND OF THE INVENTION[0002]A number of approaches are available to assist a vehicle in maintaining a central position within a driving lane. One such approach is generally referred to as a lane keeping system that includes a camera for gathering information regarding the position of the vehicle within the driving lane. For example, in one approach the lane keeping system may calculate a corrective steering torque that is a function of error between a target lane keeping position and an estimated position of the vehicle within the driving lane. The corrective steering torque is superimposed with a steering assist torque that is provided to a handwheel.[0003]The current approach of calculating the corrective steering torque may have several limitati...

AI Technical Summary

Benefits of technology

The control system described in this patent includes a control algorithm module, a comfort limit module, and a coordination limit module. The system calculates a corrective steering torque based on a target vehicle state and an estimated vehicle state, and also receives a handwheel torque. The system then determines a limited corrective steering torque based on the corrective steering torque and the handwheel torque. This represents the amount of assist torque that the system can provide safely. The system also determines a coordination torque, which represents a higher value between the limited corrective steering torque and a steering assist torque. This results in a smoother and more effective steering experience for the driver.

Problems solved by technology

The current approach of calculating the corrective steering torque may have several limitations.

For example, the application of the corrective steering torque may result in either an under-correction or an over-correction of the handwheel, depending on the amount of torque the driver is applying to the handwheel and the steering assist torque.

Another limitation is that there are challenges in determining the appropriate limit of the corrective steering torque that may be applied to the handwheel.

Also, the constant application of the corrective steering torque may negatively impact the overall steering feel of the handwheel.

Images